|Scientific Name:||Mesoplodon mirus|
|Species Authority:||True, 1913|
|Taxonomic Notes:||The peculiar disparate distribution pattern of this species suggests that there may actually be separate species or subspecies in the northern and southern hemispheres, but this has not been confirmed.|
|Red List Category & Criteria:||Data Deficient ver 3.1|
|Assessor/s:||Taylor, B.L., Baird, R., Barlow, J., Dawson, S.M., Ford, J., Mead, J.G., Notarbartolo di Sciara, G., Wade, P. & Pitman, R.L.|
|Reviewer/s:||Hammond, P.S. & Perrin, W.F. (Cetacean Red List Authority)|
There is no information on global abundance or trends in abundance for this species. It is not believed to be uncommon but it is potentially vulnerable to low-level threats and a 30% global reduction over three generations cannot be ruled out (criterion A).
|Range Description:||True's beaked whales appear to have a disjunct, anti-tropical distribution (Mead 1989, MacLeod et al. 2006). In the Northern Hemisphere, they are known only in the North Atlantic, from records in eastern North America (Nova Scotia to Florida), Bermuda, Europe to the Canary Islands, the Bay of Biscay, and the Azores. They also occur at least in the southern Indian Ocean, from South Africa, Madagascar, southern Australia and the Atlantic coast of Brazil (MacLeod et al. 2006). The species does not generally occur within 30° north or south of the equator, which may indicate that the northern and the southern subpopulations are isolated from one another. This is supported by morphological and coloration differences (Ross 1969, Ross 1984).|
Native:Australia; Bahamas; Bermuda; Brazil; Canada; France; Ireland; Madagascar; Morocco; Mozambique; Portugal (Azores, Portugal (mainland)); South Africa; Spain (Canary Is., Spain (mainland)); United Kingdom; United States
|FAO Marine Fishing Areas:||
Atlantic – northeast; Atlantic – northwest; Atlantic – southeast; Atlantic – western central; Indian Ocean – eastern
|Range Map:||Click here to open the map viewer and explore range.|
Until recent years, True’s beaked whales have been only rarely identified at sea, and there are no estimates of abundance. However, the species is not thought to be rare in the North Atlantic.
There is no information on trends in the global abundance of this species.
|Habitat and Ecology:||
M. mirus is probably a deep water pelagic species, like other ziphiids (Houston 1990).
Like other members of the genus, stranded animals have had squid (mostly Loligo spp.) in their stomachs. They may also take fish, at least occasionally. Stable isotope analysis has found that this species feeds at a similar trophic level to other Mesoplodon species with which it is sympatric, but at lower trophic level than Cuvier’s beaked whale and the northern bottlenose whales which suggests that it feeds on smaller prey than these latter species (MacLeod 2005).
Almost no information is available on the threats and status of this species. It appears never to have been hunted. Entanglement in fishing gear, especially gillnets in deep water (e.g., for billfish and tuna), is probably the most significant threat.
This species, like other beaked whales, is likely to be vulnerable to loud anthropogenic sounds, such as those generated by navy sonar and seismic exploration (Cox et al. 2006)
As a temperate water species, the strap-toothed whale may be vulnerable to the effects of climate change as ocean warming may result in a shift or contraction of the species range as it tracks the occurrence of its preferred water temperatures (Learmonth et al. 2006). The effect of such changes in range size or position on this species is unknown.
Evidence from stranded individuals of Mesoplodon mirus indicates that they have swallowed discarded plastic items. This may eventually lead to death (e.g. Scott et al. 2001).
|Conservation Actions:||The species is listed in Appendix II of CITES. Research is needed to determine the impacts of potential threatening processes on this species.|
Balcomb, K. C. and Claridge, D. E. 2001. A mass stranding of cetaceans caused by naval sonar in the Bahamas. Bahamas Journal of Science 8(2): 2-12.
Cox, T. M., Ragen, T. J., Read, A. J., Vos, E., Baird, R. W., Balcomb, K., Barlow, J., Caldwell, J., Cranford, T., Crum, L., D'Amico, A., D'Spain, A., Fernández, J., Finneran, J., Gentry, R., Gerth, W., Gulland, F., Hildebrand, J., Houser, D., Hullar, T., Jepson, P. D., Ketten, D., Macleod, C. D., Miller, P., Moore, S., Mountain, D., Palka, D., Ponganis, P., Rommel, S., Rowles, T., Taylor, B., Tyack, P., Wartzok, D., Gisiner, R., Mead, J. and Benner, L. 2006. Understanding the impacts of anthropogenic sound on beaked whales. Journal of Cetacean Research and Management 7(3): 177-187.
Fernández, A., Edwards, J. F., Rodriguez, F., Espinosa, A., De Los Monteros, Herraez, P., Castro, P., Jaber, J. R., Martin, V. and Arebelo, M. 2005. "Gas and fat embolic syndrome" involving a mass stranding of beaked whales (family Ziphiidae) exposed to anthropogenic sonar signals. Veterinary Pathology 42: 446-457.
Gomercic, H., Gomercic, M. D., Gomericic, T., Lucic, H., Dalebout, M., Galov, A., Skrtic, D., Curkovic, S., Vukovic, S. and Huber, D. 2006. Biological aspects of Cuvier's beaked whale (Ziphius cavirostris) recorded in the Croatian part of the Adriatic Sea. European Journal of Wildlife Research 52(3): 182-187.
Houston, J. 1990. Status of True's beaked whale, Mesoplodon mirus, in Canada. Canadian Field-Naturalist 104: 135-137.
Jepson, P. D., Arebelo, M., Deaville, R., Patterson, I. A. P., Castro, P., Baker, J. R., Degollada, E., Ross, H. M., Herraez, P., Pocknell, A. M., Rodriguez, F., Howie, F. E., Espinosa, A., Reid, R. J., Jaber, J. R., Martin, V., Cunningham, A. A. and Fernandez, A. 2003. Gas-bubble lesions in stranded cetaceans. Nature 425: 575-576.
Learmonth, J. A., Macleod, C. D., Santos, M. B., Pierce, G. J., Crick, H. Q. P. and Robinson, R. A. 2006. Potential effects of climate change on marine mammals. Oceanography and Marine Biology: An Annual Review 44: 431-464.
Macleod, C. D., Perrin, W. F., Pitman, R. L., Barlow, J., Balance, L., D'amico, A., Gerrodette, T., Joyce, G., Mullin, K. D., Palka, D. L. and Waring, G. T. 2006. Known and inferred distributions of beaked whale species (Ziphiidae: Cetacea). Journal of Cetacean Research and Management 7(3): 271-286.
MacLeod, C. D., Santos, M. B., Lopez, A. and Pierce, G. J. 2005. Relative prey size consumption in toothed whales: implications for prey selection and level of specialization. Marine Ecology Progress Series 326: 295-307.
Malakoff, D. 2002. Suit ties whale deaths to research cruise. Science 298: 722-723.
Mead, J. G. 1989. Beaked whales of the genus Mesoplodon. In: S. H. Ridgway and R. Harrison (eds), Handbook of marine mammals, Vol. 4: River dolphins and the larger toothed whales, pp. 349-430. Academic Press.
Ross, G. J. B. 1969. Evidence for a Southern Breeding Population of True's Beaked Whale. Nature 222: 585.
Ross, G. J. B. 1984. The smaller cetaceans of the south east coast of southern Africa. Annals of the Cape Provincial Museums (Natural History) 15: 173-410.
Scott, M. D., Hohn, A. A., Westgate, A. J., Nicolas, J. R., Whitaker, B. R. and Campbell, W. B. 2001. A note on the release and tracking of a rehabilitated pygmy sperm whale (Kogia breviceps). Journal of Cetacean Research and Management 3(1): 87-94.
Wang, J. Y. and Yang, S. C. 2006. Unusual cetacean stranding events of Taiwan in 2004 and 2005. Journal of Cetacean Research and Management 8: 283-292.
|Citation:||Taylor, B.L., Baird, R., Barlow, J., Dawson, S.M., Ford, J., Mead, J.G., Notarbartolo di Sciara, G., Wade, P. & Pitman, R.L. 2008. Mesoplodon mirus. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 22 May 2013.|
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